The invention relates generally to dielectric couplers installed in fluid lines to inhibit corrosion and wasting of two interconnected fluid conduits, made of dissimilar metals. More particularly, the invention pertains to an electrolysis-resistant coupling assembly for valves installed within fluid lines, for isolation or flow control.
Fluid pumps are often provided with a valve either on their inlet line or their outlet line, to provide flow control or fluid isolation. The valve assembly is typically manufactured from copper material. The pump inlet or outlet line, on the other hand, is usually a galvanized steel pipe. Owing to the destructive electrolysis which occurs when these two dissimilar metals are mechanically and electrically interconnected, a dielectric coupler is provided between the pump and the valve. The dielectric coupler allows the pump and the valve to be mechanically and hydraulically interconnected, but electrically isolated.
A conventional dielectric coupler for the valve application includes two components, a pump flange and a mating flange. The pump flange is connected to the galvanized pump line. The mating flange is connected a plumbing fitting which is either soldered to or threaded upon the connector to the valve. Bolts and nuts are used to secure the two flanges together. To provide electrical isolation between the two flanges, a rubber gasket and insulating bolt and nut sleeves are provided. The rubber gasket isolates the interface region between the opposing faces of the flanges. The dielectric sleeves electrically isolate the nuts and bolts from both of the flanges, while allowing a mechanical interconnection to exist between them.
The disadvantages of this construction arise during service of the pump, for example, where removal of the pump is necessary. The working space between the components is such that entire disassembly of the dielectric coupler is required to remove the pump. And this process must be performed in reverse after the pump is repaired.